Shock absorber for a two-wheeled vehicle

ABSTRACT

To provide a shock absorber that can effectively absorb a large amount of energy generated in case of a collision. A lattice body of synthetic resin is formed by reducing the thickness of a plurality of plate ribs gradually from the proximal ends to the distal ends and disposing the plate ribs intersecting with each other. The lattice bodies are arranged in a stack such that the direction of the plate ribs extending from the proximal ends toward the distal ends is oriented in an impact direction.

CROSS-REFERENCE TO RELATED APPLICATIONS

This nonprovisional application is a Continuation of U.S. applicationSer. No. 10/207,987, filed Jul. 31, 2002, now U.S. Pat. No. 6,637,786,the entirety of which is hereby incorporated by reference, and for whichpriority is claimed under 35 U.S.C. § 120. This application also claimspriority under 35 U.S.C. § 119(a) on Patent Application No. 2001-239973filed in Japan on Aug. 7, 2001, the entirety of which is herebyincorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a shock absorber for a two-wheeledvehicle. In particular, the present invention relates to a shockabsorber for a two-wheeled vehicle for effectively protecting anoccupant against a frontal crash of the two-wheeled vehicle.

2. Description of Background Art

A shock absorber is used in an automotive vehicle for protectingoccupants in case of a collision. For example, shock absorbers areprovided inside of pillar garnishes for protecting the heads of theoccupants and inside of the door trims for protecting the backs or thechests of the occupants and the like in case of a side collision. Resinribs that can be manufactured at relatively low cost have been in heavyusage as shock absorbers (See JP-A-8-164810, JP Patent No. 2978083,etc.).

However, with regard to two-wheeled vehicles, the absorption of energyin case of a collision has not been examined so far.

A shock absorber for a two-wheeled vehicle is required to absorb a muchlarger amount of energy in comparison with that for an automotivevehicle. For example, in the case of an automotive vehicle, kineticenergy to be absorbed Ek=½ mv² is 102.1 [J], which is determined basedon the energy generated when a dummy head of 4.54 kg in mass clashes ata speed of 15 mile/h (=6.71 m/s). In the case of a two-wheeled vehicle,kinetic energy to be absorbed Ek is 9646 [J], where the vehicle mass is100 kg, and the traveling velocity is 50 km/h (=13.89 m/s). Accordingly,an incommensurably large energy absorption must be realized.

Assuming that a resin rib for an automotive vehicle is used, the heightof the rib is in the order of 60 mm at most. Accordingly, a considerablylarge area is required on the two-wheeled vehicle when the resin rib,having the same absorption stroke, is applied thereto, which is actuallyimpossible. The shock absorber is to be mounted at the front end of thetwo-wheeled vehicle. Accordingly, it is impossible to enlarge the frontarea thereof. On the other hand, assuming that a method of increasingthe height of the resin rib is employed, the rib may beever-increasingly thicker because it is necessary to provide a draftangle for manufacturing reasons. This results in a disadvantage in thata generated load increases.

SUMMARY OF THE INVENTION

In order to solve the aforementioned problems, it is an object of thepresent invention to provide a shock absorber for a two-wheeled vehiclethat effectively absorbs a large energy generated in case of a collisionand that may be easily mounted on a two-wheeled vehicle.

In order to achieve the aforementioned object, according to a firstaspect of the present invention, a shock absorber for a two-wheeledvehicle includes shock absorbing members of synthetic resin. Each of theshock absorbing members comprise a lattice body including a plurality ofplate ribs reduced in thickness from the proximal ends toward the distalends and being disposed intersecting with each other. The lattice bodiesare arranged in a stack in such a manner that the direction of the plateribs extending from the proximal ends toward the distal ends is orientedalong the fore-and-aft direction of the two-wheeled vehicle. The latticebodies are mounted at the front end of the two-wheeled vehicle.

According to a second aspect of the present invention, a shock absorberfor a two-wheeled vehicle includes shock absorbing members of syntheticresin. Each of the shock absorbing members comprises a lattice bodyincluding a plurality of plate ribs reduced in thickness from theproximal ends toward the distal ends and disposed intersecting with eachother. A tabular basal plate is provided for shielding each latticespace of the lattice body molded integrally with each other. The latticebodies are arranged in a stack in such a manner that the direction ofthe plate ribs extending from the proximal ends toward the distal endsis oriented along the fore-and-aft direction of the two-wheeled vehicle.The lattice bodies are mounted at the front end of the two-wheeledvehicle.

The shock absorber for a two-wheeled vehicle according to a third aspectof the present invention includes the lattice opening at the center ofthe lattice body being made larger than the lattice openings formed onthe portion other than the center.

The shock absorber for a two-wheeled vehicle according to a fourthaspect of the present invention includes a part of the plate ribspositioned in the central area of the lattice body being thinned outwhen forming the lattice body by disposing a plurality of plate ribsintersecting with each other.

According to the first aspect of the present invention, the latticebodies are arranged in a stack in such a manner that the direction ofthe plate ribs extending from the proximal end toward the distal end isoriented along the fore-and-aft direction of the two-wheeled vehicle.The lattice bodies are mounted at the front end of the two-wheeledvehicle. Arranging the lattice bodies in a stack (stacking latticebodies) contributes to secure a large shock absorbing stroke for afrontal collision of the two-wheel vehicle, thereby a large impact to beabsorbed as desired. In addition, since the shock absorbing members arearranged in a stack, the height of the plate rib in the lattice body,which constitutes each tier, may be reduced to the value in the order of60 mm, so that the proximal end of the rib is prevented from being toothick even when a draft angle is provided, and thus such disadvantagethat the generated load increases may not arise.

According to the second aspect of the present invention, the shockabsorbing members including the lattice body and the basal plate moldedintegrally with each other are arranged in a stack. In the case whereeach of the shock absorbing members arranged in a stack is subjected toan impact load, the basal plate receives the impact load as a whole in afirst place. The impact load is then transmitted to each plate rib, andthe plate ribs are crushed continuously to absorb the impact loadeffectively.

According to the third and fourth aspects of the present invention, thelattice opening at the center of the lattice body is made larger thanthe lattice openings formed on the portion other than the center.Alternatively, a part of the plate ribs positioned in the central areaof the lattice body is thinned out in forming a lattice body bydisposing a plurality of plate ribs intersecting with each other. Thestrength of the shock absorber formed by arranging the shock absorbingmembers in a stack is low at the portion near the central axis incomparison with the cases in which all the openings are the same in sizeas a whole, and in which thinning-out is not made, and thus it crushesstably when being subjected to an impact load.

Further scope of applicability of the present invention will becomeapparent from the detailed description given hereinafter. However, itshould be understood that the detailed description and specificexamples, while indicating preferred embodiments of the invention, aregiven by way of illustration only, since various changes andmodifications within the spirit and scope of the invention will becomeapparent to those skilled in the art from this detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from thedetailed description given hereinbelow and the accompanying drawingswhich are given by way of illustration only, and thus are not limitativeof the present invention, and wherein:

FIG. 1 is an explanatory perspective view illustrating a shock absorbermounted on a two-wheeled vehicle according to one embodiment of theshock absorber of the present invention;

FIG. 2 is a vertical cross sectional view of the shock absorber;

FIG. 3 is an exploded perspective view of the shock absorber;

FIG. 4 is a drawing viewed in the direction shown by the arrow X—X inFIG. 3;

FIG. 5 is a vertical cross sectional view of the shock absorbing member;

FIG. 6 is a plan view of the shock absorbing member;

FIG. 7 is an explanatory drawing showing the progress of the shockabsorption;

FIG. 8 is a graph of the generated load with respect to thedisplacement;

FIG. 9 is a graph of the generated load with respect to the timeinstants; and

FIG. 10 is an explanatory perspective view of a shock absorber accordingto another embodiment mounted on the different type of the two-wheeledvehicle from the one shown in FIG. 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A shock absorber for a two-wheeled vehicle of the present invention(hereinafter, referred to simply as “shock absorber”) will now bedescribed in detail with reference to the accompanying drawings. FIGS. 1to 9 show one embodiment of the shock absorber according to the presentinvention. FIG. 1 is an explanatory perspective view illustrating ashock absorber mounted on a two-wheeled vehicle. FIG. 2 is a verticalcross sectional view of the shock absorber shown in FIG. 1. FIG. 3 is anexploded perspective view of the shock absorber. FIG. 4 is a drawingviewed in the direction represented by the arrow X—X in FIG. 3. FIG. 5is a vertical cross sectional view of the shock absorbing member. FIG. 6is a plan view of the shock absorbing member. FIG. 7 is an explanatorydrawing showing the progress of the shock absorption. FIG. 8 is a graphof generated loads with respect to displacements. FIG. 9 is a graph ofgenerated loads with respect to the time instants. In FIGS. 1 and 2, thehollow arrows represent the direction of the impact load generated incase of frontal collision.

The shock absorber includes shock absorbing members 1 each including alattice body 2 of synthetic resin. Each of the lattice bodies are formedby reducing the thickness of the plate ribs 2 a gradually from theproximal ends 21 to the distal ends 22 and disposed intersecting witheach other. The lattice bodies 2 are arranged in a stack in such amanner that the direction of the plate ribs 2 a extending from theproximal ends 21 toward the distal ends 22 is oriented along thefore-and-aft direction of a two-wheeled vehicle 9. The shock absorber inFIG. 1 includes the shock absorbing members 1 stacked in six-tierconstruction. The exploded perspective view in FIG. 3 shows only threeshock absorbing members 1 of the three shock absorbing members.

The lattice body 2 is formed of synthetic resin and is formed bydisposing plate ribs 2 a composed of plate portions intersecting witheach other so as to form a lattice in the direction of frontalcollision. The lattice body 2 is formed so as to be capable of beingbuckled or deformed easily by an external force exerted in case of acollision. Accordingly, the lattice body exercises shock absorbingcapability for absorbing the impact of the collision. More specifically,each plate rib 2 a constructing the lattice body 2 has a taperedconfiguration having a smaller thickness t₁ at the distal end 22 incomparison with a thickness t₂ at the proximal end 21 (FIG. 4).Accordingly, the thickness t of the lattice body 2 decreases graduallytoward the distal end 22. When an impact load is exerted, buckling anddeformation proceed gradually from the distal end portion 22 of thelattice body 2 that is low in strength so that the impact pressure iseffectively absorbed. In addition, by arranging the lattice bodies 2 ina stack (stacking the lattice bodies 2), the impact load can be absorbedmore effectively. Although vertical ribs 2 a ₁ and lateral ribs 2 a ₂ ofthe plate ribs 2 a forming a lattice are plates having the sameconfiguration in this embodiment, the thickness and the like of thevertical ribs 2 a ₁ and the lateral ribs 2 a ₂ can be selectedseparately as needed.

With effective shock absorption taken into consideration, the plate rib2 a forming the lattice body 2 preferably has a height in the rangebetween 30 mm to 60 mm, a thickness t₁ of the distal end 22 in the rangebetween 0.5 mm to 1.0 mm, and a thickness t₂ of the proximal end 21 inthe range between 1.0 mm to 2.5 mm. The dimensions of the lattice body 2itself are such that the vertical dimension A is in the order of 140 mm,the lateral dimension B is in the order of 200 mm, the height is 30 mmto 60 mm as described above, and the pitches of the plate ribs 2 aforming the lattice spaces 23 are in the order of 20 mm to 30 mm. Theshock absorbers 1 are then horizontally stacked into a several-tierconstruction (six tier in this embodiment), and mounted at the front endof the two-wheeled vehicle 9. The shock absorbers are covered by a cover5 as shown in FIG. 1.

Although the shock absorber in the present invention simply comprises alattice body 2, it is further preferable to use the shock absorbingmember 1 formed of synthetic resin including the lattice body 2 and abasal plate 3 for shielding the lattice space 23 molded integrally withrespect to each other. The shock absorbing members each including thelattice body 2 and the basal plate 3 molded integrally with respect toeach other are arranged in a stack. More specifically, the shockabsorbing members are arranged horizontally into a several-tierconstruction so that the distal ends 22 of the plate ribs 2 a abutagainst the basal plate 3 of the shock absorbing member 1 to be disposedadjacent thereof. When an impact load is exerted on the shock absorberincluding the shock absorbing members 1, arranged in a stack, the basalplate 3 receives the impact load as a whole in a first place. The impactload is then transmitted to each plate rib 2 a to cause buckling anddeformation, so that the impact load can be sufficiently absorbed.

The resin material employed for forming the shock absorbing members 1 ispreferably a thermoplastic resin such as PP, PPF, ABS, PC/ABS (alloy ofpolycarbonate and ABS), and the like.

The basal plate 3 is a tabular body for shielding the lattice space 23by being in contact with the lattice body 2. The basal plate 3 in thiscase is, as shown in FIGS. 2 and 3, a top board that comes into contactwith the lattice body 2 on the proximal sides 21 of the lattice ribs.The basal plate 3 and the lattice body 2 are integrally molded andprovided in such a manner that the basal plate 3 covers the latticeopening surface on the proximal side 21 formed by the lattice ribs 2 a.The tabular basal plate 3 is a single unit including the basal plate 3and the lattice body 2 including plate ribs 2 a being reduced inthickness t from the proximal ends 21 toward the distal ends 22 andprovided on the basal plate 3 so as to stand upright thereon in the formof a lattice. The basal plate 3 is mounted at the front end 91 of thetwo-wheeled vehicle oriented in such a manner that the basal plate 3faces toward the direction of frontal collision. A lattice opening S ofeach shock absorbing member 1 faces toward the rear of the vehicle (FIG.2). When the shock absorber is subjected to an impact load, the basalplate 3 receives the load as a whole in a first place. The load can thenbe dispersed to the respective plate ribs 2 a of the lattice body 2. Thethickness of the basal plate 3 is required to be such that it hasrigidity to some extent so as to be capable of receiving the impact onan entire area thereof. In this case, the basal plate 3 having athickness of 2 mm is employed. It is also possible to enforce the basalplate 3 by providing a flange for securing the rigidity as needed.

Although the basal plate 3 is provided so as to cover the surface on theproximal side 21 of the lattice body 2 (FIG. 5(a)), the basal plate 3must only be able to shield the lattice space 23. For example, as inFIGS. 5(b) and 5(c), the basal plate 3 can be provided in such a mannerthat the basal plate 3 traverses through the interior of the latticebody 2. FIG. 5(b) shows an example in which plate ribs 2 a, 2 a extendupright from both sides of the basal plate 3 and intersect with eachother with the thickness thereof being decreased gradually from theproximal ends 21 toward the distal ends 22 to form the lattice bodies 2.In other words, a single unit of the basal plate 3 and lattice bodies 2,2 is formed on both sides thereof. FIG. 5(c) shows an example in which alattice body 2 including plate ribs 2 a being reduced in thickness fromthe proximal ends 21 toward the distal end 22 is provided on one side ofthe basal plate 3 so as to stand upright. Bodies 4 in cross shape inside view include plate ribs 2 a being reduced in thickness from theproximal ends 21 toward the distal ends 22. The bodies 4 are providedupright on the other side thereof. Both examples shown in FIGS. 5(b) and5(c) are provided with draft angles on the lattice body 2. Cross-shapedbodies 4 extend from both sides of the basal plate 3. Accordingly, thereis no problem in manufacturing. The cross-shaped bodies 4 areaccommodated in the lattice space 23 of the lattice body 2 of the nexttier when the shock absorbing members 1 are arranged in a stack to forma shock absorber. When an impact load is exerted thereon, thecross-shaped bodies 4 are buckled and deformed from the distal ends 22,which are low in mechanical strength. Accordingly, an impact can beabsorbed with the cross-shaped bodies. The cross-shaped body 4 iseffective when there is a limit in the overall height of the stackedshock absorbers.

Furthermore, in this embodiment, a shock absorbing member 1 is employed,in which the lattice opening S located at the center of he lattice body2 is made larger than those located on the portion other than thecenter. The present invention provides a shock absorber in which theshock absorbing members 1 (lattice bodies 2) are arranged in a stack.The plate ribs 2 a located on the outer side of the lattice body 2 canbe deformed outwardly, but those located in the center area of thelattice body 2 are trapped. In other words, the lattice body 2 is hardin the center area and flexible in the outer area. When the lattice body2 is crushed by being compressed evenly, no problem arises when crushingonly one tier of the shock absorbing member 1. However, in the case ofthe shock absorbing member 1 stacked in a multiple-tier (arranged in astack), the central portion positioned in the mid tier remains. When anyone of the outer plate ribs 2 a is crushed first, the lattice body 2tends to incline toward the crushed plate rib, and the inclined latticebody 2 is pushed outwardly of the stacked portion by the front and rearplate ribs 2 a. The plate rib F that was sprung outward cannot becrushed, which results in no energy being absorbed by the plate rib F(FIG. 7(a)). As a matter of course, misalignment of the shock absorbingmembers 1 arranged in a stack is prevented by means of a lockingmechanism, adhesion, heat welding, or the like. However, the plate rib Fstill tends to be sprung outwardly. Therefore, it is constructed so asto be crushed stably by intentionally weakening the center K of thelattice body 2 (FIG. 7(b)), or by making the lattice opening S at thecenter of the lattice body 2 larger than those located on the portionother than the center.

More specifically, the lattice is constructed as a plan view of thelattice body 2 shown in FIGS. 6(b) and 6(c) when viewed from the distalend side 22. FIG. 6 is a schematic plan view showing the state ofopening of the distal end area 22 of the lattice body 2. The latticeopening S₁ at the center of the lattice body 2 is made larger than thelattice openings S₂, S₃ located on the portion other than the center byincreasing the pitches of the vertical ribs 2 a ₁, as shown by . . . ,n₃, n₂, n₁, and increasing the pitches of the lateral ribs 2 a ₂ asshown by . . . , m₃, m₂, m₁ toward the center of the lattice body 2 asshown in FIG. 6(b). However, the lattice body 2 may be such that theplate ribs 2 a are disposed at regular pitches as shown in FIG. 6(a).Alternatively, as shown in FIG. 6(c), the lattice body 2 has a part ofthe plate ribs 2 a positioned in the central area C thinned out whenforming the lattice body 2 by disposing a plurality of plate ribs 2 aintersecting with each other. As a consequence, the lattice opening S1at the central portion becomes larger than those formed on the portionsother than the center.

With the lattice openings S located at regular intervals as shown inFIG. 6(a), the lattice body 2 is in a state as if a core K (hardportion) exists at the central axis (FIG. 7(b)). Thus, the lattice body2 inclines toward the flexible portion as it is being crushed (FIG.7(a)), thereby becoming unstable. As a consequence, the lattice body 2crushed aslant may be dropped out and the plate rib F is likely to besprung out. In contrast to this, when a part of the plate ribs 2 apositioned in the central area C is thinned out, or when the latticeopening S at the center of the lattice body 2 is made larger than thoseformed on the portion other than the center, the state is such that theaforementioned core is removed. Accordingly, the lattice bodies 2 can becrushed stably. The present embodiment includes the lattice body 2 shownin FIG. 6(c), which employs the shock absorbing member 1 provided withthe basal plate 3, and which is of six-tier construction (FIGS. 1through 4). The result of a comparative representative test is shown inFIG. 8. FIG. 8(b) shows the case in which a part of one vertical rib 2a, and a part of two lateral ribs 2 a ₂ are thinned out in the centralarea C as in the present embodiment. FIG. 8(a) shows the case in whichthey are not thinned out. Without thinning out, the generated load islowered due to a drop-off of the rib in the state where it was crushedto some extent (point W) as shown in FIG. 8(a). In addition, thegenerated load increases in the latter half (point Z) by the amountcorresponding to the energy that was not absorbed due to drop-off of theplate ribs 2 a. In contrast to this, in the shock absorber formed bystacking the shock absorbing member 1, the generated load with respectto the displacement is stable as shown in FIG. 8(b), and thus the impactof collision is well absorbed. Although it is not shown in the figure,it was recognized that the generated load is also stable as in the graphof FIG. 8(b) when the shock absorber is employed, which is formed bystacking the shock absorbing members 1 having the lattice opening S₁ atthe center of the lattice body 2 made larger than those formed on theportion other than the center as shown in FIG. 6(b).

A graph representing the relation between the generated load anddisplacement of the shock absorber according to the present embodimentis shown in FIG. 9. The shock absorber A shown in a solid line in FIG. 9is an article of the present embodiment that is thinned out. The shockabsorber B shown by a chained line is formed with lattice openings S atregular intervals without thinning out. The broken line represents anideal curve value. The shock absorber B is capable of absorbing animpact to a significant extent in comparison with that in the backgroundart. However, the shock absorber B is sagged significantly in thevertical direction or in the lateral direction, and a block of the platerib 2 a at the central portion is dropped out, whereby the generatedload is lowered once and then increases to a high value due to theoccurrence of final contact without absorbing energy completely. Incontrast to this, the shock absorber A can be compressed straightwaywithout sagging in the vertical and lateral directions, and absorbsenergy completely along substantially ideal curve.

Approximation of absorbed energy E from FIG. 9 is as follows. When thegenerated load is assumed to be F[N], and displacement is assumed to beS[m], since 40×10³[N] is continuously outputted to the extent of240[mm], the equation E=F×S=40×10³[N]×0.24[m]=9600[J] is established inthe ideal curve. This represents that the absorbed energy is almostequal to the absorbed energy Ek required for the two-wheeled vehicle 9described in the aforementioned paragraph of the description of thebackground art and thus effective countermeasures are taken.

In the shock absorber constructed as described above, the shockabsorbing members 1 having lattice bodies 2 are arranged in a stack insuch a manner that the direction of the plate ribs 2 a extending fromthe proximal ends 21 toward the distal ends 22 are oriented along thefore-and-aft direction of the two-wheeled vehicle 9, and the plate ribs2 a are reduced in thickness gradually from the proximal ends 21 towardthe distal ends 22 thereof. Accordingly, the shock absorber can absorban impact effectively. With such shock absorber mounted at the front endof the two-wheeled vehicle 9, it shows its ability satisfactorily onfrontal collision of the two-wheeled vehicle 9.

Although the front area cannot be made larger for the two-wheeledvehicle 9, a new foothold was investigated by securing a space in theorder of 360 mm in the fore-and-aft direction of the vehicle.Consequently, the problem in that the proximal portion 21 of the platerib 2 a becomes too thick due to a draft angle that must be formedthereon in case of the lattice body 2 in a single-tier construction issolved by stacking the lattice bodies. By employing stacking of thelattice bodies 2 (shock absorbing members 1), a long stroke may besecured, and thus energy may be absorbed to the last moment withoutincreasing the thickness of the plate ribs 2 a.

Furthermore, when the shock absorbing member 1 provided with the basalplate 3 on the lattice body 2 is employed, the basal plate 3 receivesthe load as a whole in a first place and then the load can be dispersedto the respective plate ribs 2 a of the lattice body 2 for allowing theplate ribs 2 a to be buckled and deformed when they receives the impactload in a stack. Accordingly, the impact load can be absorbed furthereffectively. In order that the basal plate 3 receives the impact load ina first place, it is preferable to dispose the basal plate 3 of theshock absorbing member 1 so as to face toward the direction of frontalcollision.

In addition, by thinning out a portion of the plate ribs 2 a positionedin the central area C of the lattice body 2 (or making the openings ofthe lattice positioned in the central part of the lattice body 2) largerthan those formed on the portion other than the center, energy can beabsorbed to the last moment with a stable generated load even when theshock absorbing members 1 are arranged in a stack so that energy isabsorbed in a long stroke. Even when the lattice bodies 2 arranged in astack (stacked rib blocks) are crushed, the plate ribs 2 a do not dropout, and all the ribs may absorb impact energy effectively. Therefore,it is quite effective for frontal collision of the two-wheeled vehicle 9that requires incommensurably large energy absorption in comparison withautomotive vehicles.

The present invention is not limited to the above described embodiments,and various modification may be made within the scope of the presentinvention according to the object and usage thereof. Configurations,dimensions, number, material and the like of the shock absorbing member1, the lattice body 2, the basal plate 3, and the like may be selectedappropriately according to the usage.

Although an example in which the shock absorber is mounted on thescooter-type two-wheeled vehicle 9 was shown in FIG. 1, it should beunderstood that it may also be applied to a delivery-type two-wheeledvehicle (not shown) and the like. In addition, the configuration of theshock absorbing member 1 may be formed in a pyramid shape as shown inFIG. 10. The number of tiers of shock absorbing members may be modifiedaccording to the usage.

As is described thus far, the shock absorber for a two-wheeled vehicleaccording to the present invention is capable of being mounted on thetwo-wheeled vehicle, and exercises superior effects such that it iscapable of absorbing large energy effectively in case of a collision,which is required for a two-wheeled vehicle.

The invention being thus described, it will be obvious that the same maybe varied in many ways. Such variations are not to be regarded as adeparture from the spirit and scope of the invention, and all suchmodifications as would be obvious to one skilled in the art are intendedto be included within the scope of the following claims.

1. A shock absorber, comprising: shock absorbing members of syntheticresin, each shock absorbing member including: a lattice body, saidlattice body including a plurality of plate ribs, each of said plateribs being reduced in thickness from a proximal end toward a distal endthereof and being disposed intersecting with each other, wherein saidshock absorbing members are arranged in a stack such that the directionof the plate ribs extending from the proximal end toward the distal endis oriented in an impact direction.
 2. The shock absorber according toclaim 1, wherein a lattice opening at a center of each of said latticebodies is larger than lattice openings formed on a portion of saidlattice bodies other than the center.
 3. The shock absorber according toclaim 1, wherein a portion of the plate ribs positioned in a centralarea of the lattice body is thinned out when forming the lattice body.4. The shock absorber according to claim 1, wherein said plate ribs areoriented in a plurality of rows and a plurality of columns, saidplurality of plate ribs oriented in rows intersecting with saidplurality of plate ribs oriented in columns generally at a right angle.5. The shock absorber according to claim 1, wherein said shock absorbingmembers are stacked horizontally with respect to each other with adistal end of one shock absorbing member abutting a proximal end ofanother, adjacent shock absorbing member.
 6. The shock absorberaccording to claim 1, wherein said plate ribs form a plurality oflattice spaces in each of said lattice bodies, said lattice spaces beingopen at one end and closed at another, opposite end.
 7. The shockabsorber according to claim 6, wherein said closed ends of said latticespaces are formed by a tabular basal plate, said tabular basal plateextending generally perpendicular to the impact direction.
 8. The shockabsorber according to claim 7, wherein said tabular basal plate includesa plurality of cross-shaped bodies extending in the impact directiontherefrom, said plurality of cross-shaped bodies being located on a sideof said tabular basal plate opposite to said plurality of plate ribs. 9.The shock absorber according to claim 8, wherein said pluralitycross-shaped bodies on one lattice body are located within the latticespaces of another, adjacent lattice body.
 10. A shock absorber,comprising: shock absorbing members of synthetic resin, each shockabsorbing member including: a lattice body, said lattice body includinga plurality of plate ribs forming a plurality of lattice spaces, each ofsaid plate ribs being reduced in thickness from a proximal end toward adistal end thereof and being disposed intersecting with each other; anda tabular basal plate, said tabular basal plate for shielding each ofsaid lattice spaces of the lattice body, said tabular basal plate beingmolded integrally with said lattice body, wherein said shock absorbingmembers are arranged in a stack such that the direction of the plateribs extending from the proximal ends toward the distal ends is orientedin an impact direction.
 11. The shock absorber according to claim 10,wherein a lattice opening at a center of each of said lattice bodies islarger than lattice openings formed on a portion of said lattice bodiesother than the center.
 12. The shock absorber according to claim 10,wherein a portion of the plate ribs positioned in a central area of thelattice body is thinned out when forming the lattice body.
 13. The shockabsorber according to claim 10, wherein said plate ribs are oriented ina plurality of rows and a plurality of columns, said plurality of plateribs oriented in rows intersecting with said plurality of plate ribsoriented in columns generally at a right angle.
 14. The shock absorberaccording to claim 10, wherein said shock absorbing members are stackedhorizontally with respect to each other with a distal end of one shockabsorbing member abutting a proximal end of another, adjacent shockabsorbing member.
 15. The shock absorber according to claim 10, whereinsaid tabular basal plate extends generally perpendicular to the impactdirection.
 16. The shock absorber according to claim 15, wherein saidtabular basal plate includes a plurality of cross-shaped bodiesextending in the impact direction therefrom, said plurality ofcross-shaped bodies being located on a side of said tabular basal plateopposite to said plurality of plate ribs.
 17. The shock absorberaccording to claim 16, wherein said plurality cross-shaped bodies on onelattice body are located within the lattice spaces of another, adjacentlattice body.